CI: free more disk space in the VM

.github/workflows/packages.yml

@@ -29,6 +29,7 @@ jobs:
         sudo apt purge -yq $(dpkg -l | grep '^ii' | awk '{ print $2 }' | grep -P '(cabal-|dotnet-|ghc-|libmono|php)') \
           liblldb-6.0 libllvm6.0:amd64 mono-runtime-common monodoc-manual powershell ruby
         sudo apt autoremove -yq
+        sudo rm -rf /usr/local
     - name: Build
       run: |
         BASE_COMMIT=$(jq --raw-output .pull_request.base.sha "$GITHUB_EVENT_PATH")